This invention relates to a process and apparatus for regulating an interior space temperature of a motor vehicle in which a nominal temperature is set, an interior space temperature and an exterior temperature are measured, a motor is synchronously or cyclically controlled, an adjustable control member influences a heat quantity fed into the interior space and in which a first cyclical, beat or pulse signal is created which influences the creation of a second cyclical, beat or pulse signal for controlling the motor via a comparator.
A process and apparatus of the type of this invention is set forth in German Offenlegungschrift DE-OS-29 20 717. In this known apparatus, a first pulse generator is connected to a second pulse generator as well as to a third pulse generator. The pulse generators are rectangular signal generators. An interior space temperature sensor and an exterior temperature sensor are coupled to the second pulse generator. A nominal temperature provider is coupled to the third pulse generator. Outputs of the second pulse generator and the third pulse generator are coupled to a comparator which controls a motor which, in turn, moves an adjustable control member for influencing the amount of heat fed to the interior space. In addition, the first pulse generator is coupled to the comparator.
The first pulse generator delivers pulses of equal width, each beginning with the end of a comparable pulse from the comparator. In accordance with this input signal, the first pulse generator controls the second and third pulse generators. The pulse width which the second pulse generator creates is therefore proportional to the interior space temperature and the exterior temperature. The width of the pulse from the third pulse generator is proportional to the set nominal temperature. The pulses from the second and third pulse generators are compared by the comparator. The comparator forms a difference pulse through which the motor is cyclically or synchronously controlled. According to the necessary running direction of the motor a respective terminal of the motor is grounded while the other terminal of the motor is controlled with the difference pulse.
A disadvantage of this apparatus is that three pulse generators are necessary for synchronous control of the motor so that manufacture of apparatus for carrying out this process is expensive.
This known process, and apparatus for carrying out this process, is also disadvantageous in that when regulating the interior space temperature no position signal of a motor and/or an adjustable control member is respected so that it is not possible to quickly and exactly regulate and set the amount of heat fed to the interior space nor does such regulation have sufficient stability.
Thus, it is an object of this invention to provide a process and an apparatus for regulating the interior space temperature of a motor vehicle which by economizing parts can be quite easily and cost effectively carried out and produced and which provides quick, simple, and exact interior space temperature dependent upon a predetermined nominal temperature, a measured interior space temperature, a measured exterior temperature, and a position signal of an adjustable control member.